"Joshua Wong: 4 years, 8 months"
Joshua Wong should get much more than that, he will never get hired by anybody in HK, Macao or China ... even Taiwan didn't want him ... he is simply a trouble maker, no other skills for real work
When he will get free? .. hopefully another trial for something else when he is free
Well it's been several years, but from what I remember he did not play a leading role in 2019 (not like in 2014). The court probably found the evidence was not enough to justify a severe punishment.
In any case, I think they took the correct approach with relatively lenient sentences. The greatest victory is when Joshua Wong is just another name, because nobody remembers or cares anymore. Unless he continues to make trouble, he should be free to live out his life in obscurity. Even Puyi got a regular job after WWII.